I am seeking ways to disable installing apps with APK, i.e. make the setting "Allow apps from unknown sources" password-protected or disable completely for user.
Is there a way? Maybe it's possible from adb shell?
I am running LinageOS 13 on Lenovo Vibe A Plus and can flash 14.1 if needed.
I feel I found solution to my problem. Though it is not exactly what is in the question title, but it is perfectly does the job.
In the LineageOS there is a special setting that is located in Settings>Privacy, it is called Protected apps
In this applet you can specify any app and protect it with pattern.
Any, including Settings app, which fully covers my needs. If the user cannot enter the settings he cannot install APK as well
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